Odourisation of CO2 pipelines in the UK: historical and current impacts of smell during gas transport

Commercial scale Carbon Capture and Storage (CCS) will require CO2 to be transported from industrial point sources to storage sites, potentially over distances of hundreds of kilometres. One of the most efficient means of transporting fluids over large distances is via pipeline. Pipeline leaks can be problematic, especially when transporting colourless and odourless gases such as natural gas and CO2. One of the current methods of risk mitigation for natural gas transport is odourisation. The aim of this study is to determine why odourising has been suggested for CO2 pipeline transport and what benefit it would add. This article reviews the history of gas odourisation during pipeline transportation. It also discusses the existing practices with respect to odourant use for CO2 and natural gas transport in pipelines. Based on experience from natural gas, it is concluded that high pressure pipelines of CO2 through sparsely populated areas could have odourant added, but will gain little safety benefit. However, adding odourant to CO2 gas phase pipes could aid detection of leaks as well improve public assurance and should be considered in more detail.